M30 3.5 or Turbo £££

[mattG]

Help.

Newbie here have a 325i sport auto 89 that needs to go faster.

Sorry don't mean to go over old FAQs but,

1. What sort of budget is needed for either conversion, can do the heavy lifting my self but no good at welding.
2. How much of a disavantage is the auto ?
3. Expected BHP 2.5 turbo, 3.5 tickeled or 3.5 turbo with out spending silly £

[mattG]

Should this have been in Technical Help ?

[Theo]

I speak with no experience here, but you're a newbie not getting any attention! Basically, the 2.5 lump in standard tune is 170bhp or there abouts, the 3.5 you speak of is 212bhp standard. However the potential power you could acheive is massively variable depending on the setup, theres one guy on here who has a 350-400bhp turbo 2.5, and another with a 210+ setup, so as you can see there really is no limit or rule of thumb.

As for the disadvantages of an auto... if you are seriously going to tune your car as significantly as you are suggesting I think it would be a bit of a shame to have a gaybox on there, IMO you get much more driving pleasure out of a manual, I think just about everyone will agree with this.

When I first came on here I was looking into supercharging my 2.5, but soon realised it is a massive undertaking, and pussied out - hopefully you won't do the same - best of luck, and welcome to the zone.

Theo

[jmc330i]

Welcome to the zone mate

The Zone shop 2.5 M20 turbo conversion is good for atleast 250bhp - thats using the late 2.5 engine with stock internals. Speak to Ant the turbo god.

Tobys 3.5 turbo is up and running and the last estimate seemed to be around the 300bhp mark, again with a standard engine.

Turbo power seems to be the way forward

[Turbo-Brown]

Yeah, turbo power is the way forward!

If you can do all the work yourself you can keep the cost reasonable and the M20 engine seems to respond well to boost

Definately lose the auto though!

[fuzzy]

how far can you push the m20 engine with F/I before the internals need serious work? depends how far you want to go but you definately need to lose the auto box

[Ant]

M20 engines are bombproof as long as they are well maintained.

350 bhp is poss with stock internals on the right turbo.

drop the CR to 8:1 and enjoy 25 psi without issue, again, the key is in the prep, a welded head is certainly advisable as are 12.9 garde head bolts or a stud n nut conversion.

you'd not get the best outa this on an auto box though, as boost depends on load more than rpms.

[m-dtech]

M20 engines are bombproof as long as they are well maintained.

350 bhp is poss with stock internals on the right turbo.

drop the CR to 8:1 and enjoy 25 psi without issue, again, the key is in the prep, a welded head is certainly advisable as are 12.9 garde head bolts or a stud n nut conversion.

you'd not get the best outa this on an auto box though, as boost depends on load more than rpms.

you talk of a welded head? welding what exactly ?

[mattG]

Thanks for the input guys
Sounds Turbo might be lighter work to go for leaving the stock lump in, I know it will still take time but how much money on parts if i do the bolting on etc.
Am I still asking silly Qs ?
Also does Ant have a step by step guide.
I guess if all goes well on BHP front gaybox will be replaced when it leaves nasty mess on the road, thanks again

[WillG]

you talk of a welded head? welding what exactly ?

this is a welded m20 head done by QEP, you dont need to weld it up this much tho, onlt the middle section on the water jacket so they all look like cylinder 6 on this head. Doing this helps support the head gasket so it stops belowing out. The gap between the cylinder and waterjacket is quite small and the gasket gets pushed out into waterjacket and if this happens it can also crack your head

[WillG]

Ive also seen PPF weld over the top of the cam journal between rocker shaft supports on high rpm engines. pictures on pure-pf and bf.com forum.

Better resize your avatar mattG

[mattG]

Hows This

[WillG]

fine, not sure what limit is, but mines smaller then theo325 so must be ok i guess.

Ebay dumpvalve, wastegate and intercooler (or scrap yard intercooler), recon HX35 turbo, stretch bolts need replacing with normal bolts. Then Megasquirt fuel and maybe spark which depending on where you are ant might be able to sort you out with.
Manifold and injectors im not sure where you will get these from there is alot of places but none really cheap or easy from what ive seen. Thats your best bet for a safe budget system imo, if you got more to spend would probly go for a better wastegate and then a thicker MLS headgasket

[Toby_Unna]

my 2p

depends how much you ultimately want.

any half decent 2.5 turbo conversion will be quicker (and feel quicker) than a standard m30, for roughly similar work/cost. Ant's car felt stronger than my standard 3.5 even running pretty low boost.

however if you want a lot of power, do the m30 first, then turbo it if it's not quick enough. it's a nice solid base for a powerful engine!

[mattG]

say you had the turbo set up on the 2.5, could it be swaped on to a 3.5 ie would it use the same electronics, turbo, manifolds, intercooler etc?
what sort of cost is involved in manifold fabrication?

[Turbo-Brown]

Turbo, possibly.
Manifold, no.
Intercooler, yes.
Electronics, yes although injectors might need changing.

Think I spent a total of about £400 odd on making my manifold and the entire exhaust system (nothing suitable was available off the shelf)

[Ant]

inj and management will swop over, could use the same turbo and IC but a new manifold or adapter will be required.

M20 turbo with a CR drop will see 400 HP no problemo

mines coming off the road after the 20th for some more mods

[mattG]

when you say 400 pounds is that parts & frabrication?

[Jon_Bmw]

when you say 400 pounds is that parts & frabrication?

YOU WISH, i think ant said 400bhp(brake horse power) most definatly not £400!!!!

Edit: turbo brown was refering to his exhaust manifold and exhaust, there is so much more!

[Toby_Unna]

Think I spent a total of about £400 odd on making my manifold and the entire exhaust system

Alex made his system from scratch because it's a twin turbo setup, i don't think that figure includes labour costs

[Turbo-Brown]

The £400 was for head flanges, turbo flanges and pipe plus some sheet to make the silencer out of.

Did all the fabrication and machining myself though which is the expensive part I guess!

[mattG]

is the Twin tubo sequential? the jap boys tend to go single!
by the way my last car was a subaru legarcy GT 4X4 auto wagon twin sequential turbo 260 bhp std. had a posom bourne racinging chip and decat estmated 34 bhp, was quick

[WillG]

Alex's isnt sequential its 2 turbos coming of 3 cylinders each, it is a nice setup but I think he has said himself its more effort for same as you get from single one. HX35 is going to be best bet for cheap turbo, manifold will be your problem if you cant fabricate you need to pay someone to make you one. PPF do one for about £450-£500 in mild steel (best design and proven to 600+hp), there are chinese/proturbo ones for about £400 in stainless and jon volk (666) are about £600+ in stainless and I doubt you will find many fabricators willing to make you one for alot less, flanges and pipe is £100-150 and alot more for stainless but I wouldnt bother with stainless. You also have the log type TCD and BBR? if they still do them but im not sure how much these sell for. Mine will be up soon, its got to be done before august. be busy cos bro decided to let me derust rest rest of his motor , got intercooler today



450x300x75 pretty useless pic but will show it fitted before august

[Turbo-Brown]

Yeah, it's an interesting setup, but I only did it because I happened to have a pair of turbos kicking about.

Quite fancy having a go at a twin sequential system actually for the mega low end torque complemented by top end pull.

Don't you need the american style seperate manifolds to make some of the adaptors available work?

Would be quite happy to make an adaptor for the single piece cast manifold, can't imagine it coming to more than a couple of hundred quid TBH.

[mattG]

thanks for that Will, have been looking at 325td urbo 325 artical and saw Ants BBR &T3 set up, is that like your one and how much could be very interested

[WillG]

I dont know if they still do the BBR one, isnt ants for sale?, you should buy that tbh. Like alex said the adapter is a option I forgot about that, I got some LHD manifolds for £20 sent to me from US and im not using them, if the RHD doesnt work you could get some LHD ones easy, dont see why it wouldnt tho. But there are ready made adapter for the LHD style manifolds which are quite cheap, probly £300 to get it here from US but you have to be careful where wastegate pipes are becuase one that I saw jon volk do would be very close if not in contact with steering shaft. Im sure he could put one somewhere else for you tho.

[mattG]

Sorry guys a bit confused about the adapter, is that for a std manifold?

[e30_Turbo]

The adapters you can get are really only for LHD due to space issues, also they're never going to deliver the flow you need for a decent power level.

The BBR manifold, Ant has 2 by the way, is ideal, very fat, strong and fits into the engine bay really well. My tubular manifold if large and has eaten up most of my downpipe space so I'm having to work my way around it to get the exhaust finished, proper PITA.

Which ever you buy just make sure it fits a RHD car as there are soo many that don't!

HTH, Mark.

[Turbo-Brown]

Such a shame BMW didn't symetrically space the studs around the port!

If they had we could flip the standard manifold and then make a very short adaptor.

Ho well

[gcorky]

Such a shame BMW didn't symetrically space the studs around the port!

If they had we could flip the standard manifold and then make a very short adaptor.

Ho well

like the one i sold blingsta!m20 flip with t3 adapter....was for sale for weeks!!!

[WillG]

matt the RHD and LHD stock manifolds are totaly different btw, LHD is 2 piece and RHD 1 piece. Without looking at downpipe space which is a an important thing ive only seen jon volks adapter that will hit steering but probly a couple that wont leave much space for a straight downpipe. I would get ants BBR manifold if he hasnt sold it or order one from PPF becuase I know they fit, thing is with PPF you will probly have to wait atleast a month for it becuase they are busy people

[mattG]

Have spoken to ant and secured his BBR, things are on the move now
going on hols today (ireland for a week) then its getting all the other bits together, on atight buget so if any body has parts to get rid of let me know,
MANY thanks to every body for the advice would like to go 3.5 but 2.5 turboed 300BHP! will do for now would like to have had professormatt's
AVR lump i'll try and sell the wife and kids in ireland cheers all mattG